Continuous fiber-reinforced thermoplastics continuously include a reinforced fiber, such as a glass fiber or a carbon fiber, in thermoplastics having relatively vulnerable mechanical intensity. The continuous fiber-reinforced thermoplastics are very excellent in mechanical intensity, rigidity, and impact performance, as compared to short fiber-reinforced thermoplastics having a length up to 1 mm or long fiber-reinforced thermoplastics (LFT) such as glass mat-reinforced thermoplastics (GMT), which have a length of about 5 to 50 mm.
In addition, the continuous fiber-reinforced thermoplastics having flexibility may be woven in a short direction or both directions and the continuous fiber-reinforced thermoplastic structure through this can be applied to products requiring various mechanical performance.
The continuous fiber-reinforced thermoplastics are generally prepared by a pultrusion method, a hot pressing method following commingle, etc.
The pultrusion method passes a bundle of the widely stretched continuous fibers to a liquid (or melting) resin tub or a die to impregnate thermoplastic resin in the bundle of the continuous fibers. The pultrusion method can increase a degree of impregnation when process conditions are optimized; however, it is difficult to control a content of thermoplastic resin, degrades flexibility, and is not easily woven.
A hot pressing method followed by commingle is a method of commingling the continuous fibers and the thermoplastic resin in a fiber type and then performing the hot pressing thereon. The hot pressed commingle fibers do not largely loss the flexibility of fibers due to the physical binding of the continuous fiber and the thermoplastic resin, such that the weaving is easy and when hot rolled pressing is performed after the weaving, the formability and impregnation are excellent and the content of the thermoplastic resin and the reinforced fiber of the continuous fiber-reinforced thermoplastics is freely controlled. However, since the thermoplastic resin is randomly mixed in the bundle of the continuous fibers, when the hot rolled pressing is performed after the weaving, the sufficient impregnation does not partially occur, the uniformity of physical properties is degraded and when the thermoplastic resin is prepared in a fiber type, it is restrictively applied to the thermoplastics having sufficient elongation characteristics in connection with workability.
Therefore, a development of the method of preparing thermoplastics-continuous fiber hybrid composite, which is easily woven, has excellent uniformity and impregnation upon the thermal melting impregnation after the weaving, and can use the thermoplastics in the various types, is urgently required.